WEST VALLEY CITY — Chuck Cox says the search for his daughter Susan Cox Powell is not over.

A day after West Valley police announced that all of their leads into the disappearance of the West Valley mother had been exhausted and the active search for her is finished barring any new information, Cox said Tuesday he plans to organize more searches to look for his daughter's remains.

"They are never going to quit. They are going to make sure they find Susan," attorney Anne Bremner said, standing next to Cox in her Seattle office building. "This family won't quit, because they can't."

Bremner also said an investigation from a Utah federal agency is still ongoing, although she did not know which agency. She believes the investigation is somehow tied to Steven Powell and what he may have known about his daughter-in-law's disappearance.

The U.S. Attorney's Office for Utah said it and the FBI are no longer involved.

"The U.S. Attorney’s Office and federal law enforcement agencies in Utah have provided assistance to the West Valley City Police Department, at the police department’s request, at various times during the course of the investigation," the office said in a prepared statement. "If there are new developments in the case in the future we would be willing to assist again. At this time, however, we do not have plans to conduct any further investigation.”

West Valley Deputy Police Chief Mike Powell, who also denied the existence of any independent federal investigation, passionately took issue with reports calling the Susan Powell case "closed," even though the city announced Monday that its "active investigation" is over.

"Our case is not closed. We have a very open investigation. It will remain open until we can find Susan and find out what has happened to her," said Powell, who is not related to the Powell family in question. "It's our investigation. The investigation is still open in all aspects. If we need further assistance from our federal law enforcement counterparts, absolutely we will continue to reach out to them."

On Monday, West Valley police released more than 2,000 files containing police reports, search warrants and maps of areas where they had conducted searches for Susan Powell. Cox said now that he had copies of those maps, he plans to study them and organize private searches.

Michael Powell

One area he believes will be scrutinized soon is near Pendleton, Ore., where Michael Powell — the brother of Susan Powell's husband Josh — allegedly had car problems while driving back to Washington from Utah just two weeks after Susan went missing. He sold his 1997 silver Ford Taurus to Lindell Salvage there for $100.

West Valley police did not find out about the sold car until August or September of 2011. At that point, Deputy Chief Phil Quinlan said Michael Powell became an elevated person of interest in the Susan Powell investigation.

"We interviewed Michael shortly after we discovered his car. We went back to interview Michael about his involvement in the case. During that interview he was extremely nervous, he was evasive, he provided incorrect information about the car — he didn't know we had the car, and we broke the news to him that we had his car. He lied to us about where it broke down," Quinlan said.

West Valley detectives traveled to Pendleton and found the car "had been stripped of some parts such as the right front passenger door, taillights, steering components etc.," a police report from September 2011 states. A cadaver dog was brought to the yard and "intensely searched the back portion of the vehicle and then indicated by a final result of sitting." The vehicle was sealed in plastic by police the next day and was towed to a holding facility. It was later processed by the forensics unit.

Investigators, however, said the DNA evidence collected from the trunk did not match Susan Powell's profile.

At one point, Michael Powell went to a Colorado company in Boulder — Apollo Mapping — seeking a high resolution image of the salvage yard in Pendleton, according to police reports.

Like his father and his brother Josh, Michael Powell refused to give his full cooperation to investigators, Quinlan said Tuesday.

"He was asked a very pointed question. He was asked, 'If you knew what happened to Susan, would you tell us?' And he said, 'Absolutely not,' and it was because he was bent on protecting his brother Josh."

Police said Monday they believe Michael Powell likely had "intimate involvement" in Susan Powell's disappearance. That announcement was a big surprise for Cox, he said, especially considering that his daughter had said she always thought that he was the "most normal" person on that side of the family.

"It's clear he was deeply involved in this, and it's a shock," Cox said Tuesday.

Bremner said her suspicions were raised when Josh Powell made his brother the 93 percent beneficiary of Susan Powell's $3.5 million life insurance policy.

On Feb. 11, 2013, Michael Powell committed suicide by jumping off a seven-story parking structure in Minnesota. No suicide note or will was found.

"What caused him to commit suicide? Remorse, guilt or the fact that people were closing in," Cox said. He believes Josh Powell's suicide was also an admission of guilt.

Powell confession?

In one police report released Monday, a forensic psychologist told investigators he felt Josh Powell made what he believed was “an admission of guilt” just two days before her murdered his sons and killed himself.

When Powell mentioned a need to reconcile with the Cox family, the psychologist told him the family believed he killed their daughter and unless she came back unharmed or her body was found and the evidence showed he couldn’t have done it, the doctor doubted reconciliation would be possible.

According to the report, Powell “paused while considering these two scenarios, and then somewhat rhetorically stated (that) reconciliation with the Cox family would not be possible." Josh Powell also was concerned that he would be asked questions related to his wife’s disappearance during an upcoming polygraph exam that had been ordered by a court overseeing custody of his children.

The psychologist also said that a voice mail Joshua Powell left for his sister right before he killed himself and his children, “in his expert opinion was an additional admission of guilt in the disappearance of Susan Powell,” the report states. “The statement Joshua made was about having caused hurt to someone and was made in the past tense. (The doctor) believed this was Joshua's attempt to apologize for what he had done to his wife.”

Why no charges?

Despite the mountain of circumstantial evidence, West Valley police reiterated Tuesday that they never had enough evidence to file criminal charges against Josh Powell — either for murder or even a lesser crime such as obstruction of justice — mostly because of a lack of a crime scene and because Susan Powell's body was never found.

"There are still those legal hurdles that we have to overcome in order to reach the point we can make an arrest and file charges," Quinlan said. "The evidence that we obtained over time was focused primary on Susan's disappearance and suspected murder by Josh Powell. We never reached the legal threshold to file criminal charges.

"We did want to bring a murder charge against Josh Powell and hold him accountable for what we believe probably happened," Quinlan said. "But if you bring that case in the current condition it is, you do run a sufficient risk that the charges would either be brought down to lesser offenses or an acquittal. It was a very high stakes gamble that we were not willing to take."

But Cox said he believes there was enough circumstantial evidence and called investigators' decision not to file charges "flawed."

"I understand their reasoning as far as the crime scene and lack of a body. But I personally (think they) came to the wrong conclusion on the circumstantial evidence. I think there was plenty," he said.

Bremner concurred that circumstantial evidence can be just as strong as direct evidence in some cases.

Juan Becerra, who was working at one time as the field coordinator for the profiling unit at the FBI's headquarters in Quantico, Va., said from what he observed, West Valley police did everything they could have possibly done with the case. They were even working toward ways of filing charges without finding Susan Powell's body.

"Without a body, it's extremely, extremely difficult to charge a case. They were stuck and the D.A.'s office was stuck with a very, very difficult case," he said. "It doesn't matter what you think, it only matters what you can prove. The D.A.'s office has to go on the evidence and so does the FBI. And as much as you try, if you can't come up with clear and convincing evidence to charge, there really is no way to shake that tree so that it bears fruit in order to obtain a conviction or even charge him. And as I said, without a body it's extremely difficult to do that."

Retired FBI special agent Lou Bertram, a psychological profile coordinator who did not have an active role in the Powell investigation, said from what he observed, the case went cold after 48 hours.

"I hate to criticize the West Valley Police Department, but basically it all added up to zero. There are four people who are dead. There is no doubt Josh killed his wife," he said. "This case was finished after 48 hours, no matter what the West Valley Police Department tried."

Bertram said he would have attempted to question the Powell children earlier. He also believes West Valley police should have brought in expert help earlier in their investigation.

"Not every criminal case can end in closure. This is one," he said.

Steven Powell

One area where police and Cox agree is their belief that Josh Powell's father, Steven Powell, knows more about what happened to Susan than he's telling.

Steven Powell was sentenced to Monroe Correctional Complex in Monroe, Wash., last year after being convicted of multiple counts of voyeurism. West Vally police said Monday that they don't currently believe, however, that he had anything to do with the disappearance.

Quinlan said Tuesday: "We have investigated that component with Steve very, very thoroughly," and found it hard to believe that Josh Powell lived with him for so many months after Susan's disappearance and Steven Powell didn't see, overhear or directly talk to Josh Powell about his wife being missing.

In August of 2012, West Valley detectives attempted to interview Steven Powell in prison about Josh Powell, according to newly released police reports. He refused to give them information. But investigators commented on his body language, noting that he would noticeably shake when confronted about his own journal entries talking about the possibility of Josh Powell killing his sons before the event actually happened, and then watched as his "eyes welled with tears."

"I told Steve that he is the only one who ever expressed or knew about that danger and I asked him again what he did to stop Josh," one detective wrote.

Later, the detective grilled Steven Powell about whether he ever asked his son where he went after his wife disappeared. Steven Powell refused to answer.

"I again told Steve that since what Josh told him was a lie, and what he told the media was a lie, that Steve should commence helping us find out what Josh did with Susan's body. Steven demanded that he be returned to his cell," the report states.

According to police records, Steven Powell is currently writing a novel.

"He knows a lot more than he's telling, and obviously, so do federal authorities," Cox said.

With so much information now out in the public, Bremner said she believes the search for Susan is anything but over.

"It's difficult for the case to shut down when I think we're on the verge of somewhere," she said.